1. Field of the Invention
The present invention relates to connections between pipes and concrete structures, and in particular, the present invention relates to waterstop rings, which provide a watertight connection between pipes and concrete structures.
2. Description of the Related Art
Waterstop rings are designed to provide watertight sealing connections between pipes and concrete structures, such as connections between pipes and precast concrete manholes, or any other concrete structures to which pipes may be connected. Typically, to install a waterstop ring in such a connection, the waterstop ring is first placed over the outside surface of a pipe, and one or more clamp rings are tightened around the waterstop ring to sealingly secure the waterstop ring around the outer surface of the pipe. The pipe, with the waterstop ring attached thereto, is then positioned within an opening in the concrete structure with the waterstop ring in the middle of the wall thickness of the concrete structure. Thereafter, mortar or grout is filled or cast between the opening and the waterstop ring to embed the waterstop ring within the mortar upon curing of same. The waterstop ring prevents water from passing between the waterstop ring and the pipe, and also presents a barrier in the form of a tortuous path to block the passage of water through the mortar from one side of the concrete structure to another.
For example, in FIG. 1, a prior connection 10 between concrete structure 12 and pipe 14 is shown. Pipe 14, with waterstop ring 16 attached thereto, is installed within opening 18 of concrete structure 12 as described above, with mortar 20 cast within opening 18 and filling the space between pipe 14 and opening 18 such that waterstop ring 16 is embedded within mortar 20. Waterstop ring 16 includes a series of annular undulations 22 as well as an annular waterstop member 24, which together present a tortuous path to prevent water from passing through mortar 20 around waterstop ring from one side of concrete structure 12 to another. However, as may be seen from FIG. 1, connection 10 between pipe 14 and concrete structure 12 is a rigid connection which, disadvantageously, does not allow any movement of pipe 14 in a direction away from central axis 26 of pipe 14. Therefore, any forces applied to pipe 14 could possibly result in cracking of mortar 20, separation of waterstop ring 16 from the outer surface of pipe 14, or any other failure of watertight connection 10 between pipe 14 and concrete structure 12.
What is needed is a waterstop ring which improves upon the foregoing, in order to reduce the possibility of failure of the watertight connection between a pipe and a concrete structure.
The present invention provides a flexible waterstop ring which allows a flexible joint to be established between a pipe and a concrete structure. The waterstop ring includes an annular waterstop member projecting from an outer circumference thereof, and a pair of annular shoulder portions respectively disposed on each side of the waterstop member. The waterstop member and each of the shoulder portions each include hollow annular cavities defined therein, such that when the waterstop ring is installed in a connection between a concrete structure and a pipe, and partially embedded within mortar cast between an opening of the concrete structure and the pipe, the annular cavities allow deformation of the waterstop ring and thereby allow movement of the pipe in a tilting manner away from the central axis of the pipe.
A head portion of the waterstop ring includes the waterstop member and the flexible shoulder portions, and the waterstop ring additionally includes an annular tail portion connected to the head portion by an undulating portion. The tail portion includes a pair of clamping surfaces thereon to which at least one clamping ring may be seated and clamped to sealingly attach the tail portion of the waterstop ring to the outer surface of a pipe.
To install the waterstop ring to provide a flexible joint between a pipe and a concrete structure, the waterstop ring is first placed about a mandrel, with the tail portion folded within the central opening of the waterstop ring such that the tail portion is disposed between the head portion of the waterstop ring and the outer surface of the mandrel. Thereafter, the mandrel and waterstop ring are positioned within an opening in a concrete structure such that the head portion of the waterstop ring is disposed in the middle of the wall thickness of the concrete structure. Mortar is then poured or cast within the opening between the concrete structure and the waterstop ring, and allowed to cure. The mandrel is then removed, and the tail portion of the waterstop ring is unfolded from the central opening thereof to project from one side of the concrete structure externally of the mortar. A pipe is then fittingly inserted within the central opening of the waterstop ring, and at least one clamping ring is seated on the clamping surfaces of the tail portion and tightened to provide a firm sealing connection between the tail portion and the outer surface of the pipe. Alternatively, the waterstop ring may be integrally cast within a monolithically poured concrete structure for later shipment of the concrete structure to an installation location where a pipe is attached thereto, or, a concrete structure may be monolithically cast around the waterstop ring and pipe at an on-site location.
Additionally, a waterstop ring is provided for use with corrugated pipe, in which the tail section of the waterstop ring includes an annular ridge adapted to be seated in one of the recessed portions of the corrugated pipe. The tail section additionally includes a pair of clamping surfaces respectively disposed on each side of the annular ridge, such that when the ridge is positioned within a recessed portion of the corrugated pipe, the clamping surfaces are located against the projecting portions of the pipe which are disposed on each side of the recessed portions, thereby allowing the clamping rings to be tightened on the waterstop ring against the projecting portions of the corrugated pipe.
Advantageously, when the waterstop ring is installed in a connection between a pipe and a concrete structure, the annular hollow cavities in the waterstop member and in the flexible shoulder portions thereof allow the waterstop ring to flex, thereby allowing tilting movement of the pipe in a any direction radially away from the central axis of the pipe. In this manner, a flexible joint connection is created between the pipe and the concrete structure in which some tilting movement of the pipe is allowed, in order to reduce the possibility of stress failure of the connection. Additionally, the undulating portion of the waterstop ring may expand and compress to allow axial movement of the pipe relative to the concrete structure along the longitudinal axis of the pipe.
As with known waterstop rings, the present waterstop ring also sealingly engages the outer surface of the pipe to prevent the passage of water therebetween, and the waterstop member and shoulder portions of the waterstop ring also present a barrier in the form of a tortuous path to prevent the passage of water through the mortar from one side of the concrete structure to another.
In one form thereof, the present invention provides a flexible waterstop ring for providing a connection between a concrete structure and a pipe which has a central axis, including an annular head portion having an inner circumference and an outer circumference; and a pair of axially spaced annular shoulder portions projecting from the outer circumference, each shoulder portion having at least one annular cavity therein, wherein when the pipe is connected to the concrete structure with the waterstop ring partially embedded within the concrete structure, the at least one annular cavity allows deformation of the waterstop ring to thereby allow tilting movement of the pipe in a direction away from the central axis of the pipe.
In another form thereof, the preset invention provides a flexible joint connection, including a concrete structure having an opening therein; a pipe disposed through the opening, the pipe having an outer surface and a central axis; and a flexible waterstop ring disposed around the outer surface of the pipe and at least partially embedded within the concrete structure around the opening, the waterstop ring having a pair of axially spaced annular shoulder portions projecting radially outward from an outer circumference thereof, each of the shoulder portions defining at least one first annular hollow cavity therein, whereby the hollow cavities of the shoulder portions allow the shoulder portions to flex, thereby allowing tilting movement of the pipe in a direction away from the central axis.
In another form thereof, the present invention provides a concrete structure, including at least one wall formed of concrete; and a flexible, annular waterstop ring around which the concrete wall is cast, the waterstop ring including an annular head portion having an outer circumference and an inner circumference, the inner circumference defining an opening through the concrete wall, the head portion of the waterstop ring further including a pair of annular shoulder portions projecting radially outward from the outer circumference thereof which are embedded in the wall, each of the shoulder portions defining at least one first annular hollow cavity therein, whereby the hollow cavities of the shoulder portions allow the shoulder portions to flex.
In another form thereof, the present invention provides a method of casting a concrete structure, including the steps of providing a flexible, annular waterstop ring including a central opening, and an annular head portion attached to an annular tail portion, the head portion further including a pair of annular shoulder portions projecting radially outward from an outer circumference thereof, each of the shoulder portions defining at least one first annular hollow cavity therein, whereby the hollow cavities of the shoulder portions allow the shoulder portions to flex; folding the tail portion of the waterstop ring inwardly into the central opening; casting a concrete wall around the waterstop ring, the central opening of the waterstop ring defining an opening in the concrete wall; unfolding the tail portion outwardly of the central opening, wherein the tail portion projects outwardly of the wall; and inserting a pipe through the waterstop ring.
In a further form thereof, the present invention provides a flexible waterstop ring for providing a connection between a concrete structure and a corrugated pipe having a central axis and an outer surface defined by plurality of alternating, annular recesses and protrusions, including an annular head portion having an outer circumference; an annular tail portion connected to the annular head portion and having an inner circumference, the tail portion further including an annular ridge projecting radially inward from the inner circumference, the ridge adapted to be fitted within an annular recess of the pipe; and a pair of annular shoulder portions projecting radially outward from the outer circumference, each shoulder portion having at least one annular cavity therein, wherein when the pipe is connected to the concrete structure with the waterstop ring partially embedded within the concrete structure, the annular cavities allow deformation of the waterstop ring to thereby allow tilting movement of the pipe in a direction away from the central axis of the pipe.